This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Phospholipases catalyze the hydrolysis of membrane phospholipids, which, in turn, generates a variety of lipid second messengers. These lipid-derived products are necessary for both physiological and pathological processes. An understanding of phospholipid metabolism, as it relates to cancer, is necessary for diagnostic applications and for developing novel targeted chemotherapy. Traditionally, lipid metabolite changes have been observed by magnetic resonance spectroscopy (MRS) or by chromatographic methods. Using a combination of MRS with near-infrared (NIR) fluorescent molecular probes we are targeting phospholipase function with the goal of delineating specific cell signaling pathways in vivo. The information gained from a molecular imaging approach may lead to earlier diagnoses and improved management of disease.